As disclosed in U.S. Pat. No. 3,920,444 (Harrington et al.), it is known that biologically-active materials can be prepared from primary anilines bearing hydrocarbylthio substituents. The patentees indicate that poly(hydrocarbylthio)anilines could be used as their starting materials, but they do not disclose any such compounds or suggest how they might be made other than by implicitly disclosing 2,6-di(methylthio)aniline--a compound that could have been made by the process of Hodgson et al., Journal of the Chemical Society, 1928, pp. 162-166.
Cogolli et al., Journal of Organic Chemistry, Vol. 44, No. 15, 1979, pp. 2636-2646, show that 2,3,5-tris(isopropylthio)aniline can be prepared as a by-product in the reaction of picryl chloride with isopropylthiosodium. However, they do not teach how to make other poly(hydrocarbylthio)anilines, such as 2,4,6-tri-substituted anilines, which, by virtue of being substituted in the ortho and para positions, could be used not only as precursors for Harrington-type herbicides, etc., but as additives, such as antioxidants, in which ortho and para substituents are known to be an asset.
Doyle et al., Journal of the Chemical Society, 1963, pp. 497-506, teach that 4-chloro-2,6-di(methylthio)aniline can be prepared by the treatment of 2-(methylthio)aniline hydrochloride with sulfur chloride, followed by hydrolysis, reduction, and methylation; but they do not teach how to prepare analogous compounds having a chloro substituent in a position other than the para position.
U. S. Pat. No. 3,272,814 (Cutler et al.) discloses a process for preparing vicinally dialkylthiated anilines from suitably substituted benzothiazoles.